Heretofore, there has not been a useful means for installation on a vehicle to provide an indication of weight in the load bed or loading compartment or receptacle of a vehicle. Conventional systems for determining the vehicle weight measure the entire weight of a vehicle, or of a loaded axle of a vehicle. These systems involve a spring supported platform located at the roadway level. A vehicle is driven onto the platform so that the entire vehicle or rear axle thereof can be weighed. Such weighing systems are quite large and expensive and are suitable for use only in specialized locations. For example, such weighing systems are employed at highway truck weighing stations under the administration of State Police or other governmental authorities to determine whether or not vehicles are overweight. Since these conventional truck scales are so expensive and require considerable room for operation and manipulation of the vehicles to be weighed, trucking firms and other facilities where trucks are located generally find it unattractive to utilize these conventional devices. Consequently, weight estimates in loading are largely based on guess work, and inaccuracies of weight estimation are quite frequent.
The result of the failure of the art heretofore to provide a convenient compact load measuring system suitable for installation on a vehicle has resulted in the assessment of innumerable fines and penalties for overweight vehicles. Moreover, the highways and roadways are subjected to inordinately rapid deterioration due to the degrading effects of use by vehicles in which overweight conditions are not detected. In addition, such overweight vehicles represent a severe safety hazard in that their braking distance is significantly increased, although the driver of the vehicle may be totally unaware of the overloaded condition of the vehicle.
Furthermore, the present inaccurate weight estimating techniques frequently result in the dispatch of a truck or other commercial vehicle in an underloaded condition. That is, in many instances a vehicle departs from its loading facility only partly loaded, although the dispatcher may well have estimated the vehicle to be loaded to its maximum capacity. The result is a loss of cartage revenues due to vehicles traveling in a short-loaded condition. This inevitably leads to increased freight rates to compensate for inefficient transport conditions of vehicles.
The present invention is a compact and economical vehicle load measuring system that may be readily installed to great advantage in alleviating the foregoing problems. Unlike conventional load measuring systems, the present invention does not require a "drive-in" facility to support the entire bulk of an axle and which must extend at least beyond the width of vehicle wheel separation. Rather, small sensors are employed and are disposed between the vehicle load bed and the vehicle axle. Since the weight of the vehicle chassis does not vary significantly, it is unnecessary to repeatedly measure this portion of the vehicle weight as is done in conventional weighing facilities. Rather, it is only necessary to measure the variable load which is carried in the load bed or compartments of the vehicle. Thus, rather than employing separate scale systems as utilized in conventional truck weighing systems in order to derive the load weight by measuring the deflection of a spring, the present invention utilizes the existing leaf springs or other resilient or elastic load supporting means for the purpose of determining the load in a vehicle load bed. Such leaf springs or other elastic supporting means are supplied as standard equipment on virtually all automotive vehicles, and are interposed between the axles and chassis of the vehicle.
A further application of the invention is in connection with commercial facilities where vehicle loading forms a part of a transaction. For example, at grain elevators, sand and gravel yards, asphalt plants, and other bulk purchasing facilities, materials are frequently purchased on the basis of weight as determined by conventional truck weighing scales. In such facilities, long queue lines frequently form at the truck weighing scales during periods of heavy use. Utilizing the present invention, however, an individual truck need not wait in a line for access to a scale, but instead load on the chassis of the vehicle can be readily and easily determined. The invention also has great utility in association with moving and storage vans. In these vehicles, inaccuracies in load estimating frequently give rise to customer complaints and suspicions of inaccurate weight. By employing the present invention in connection with such moving vans, the customer will be able to ascertain for himself the actual weight loaded prior to the departure of the vehicle.